Paper and pulp making cylinder mold



Nov. 20, 1928. 1,692,733

T. HARVEY PAPER AND PULP MAKING CYLINDER MOLD Filed Aug. 23, 1927 2 Sheets-Sheet l INVENTOR.

By m

A TTORNE Y.

Nov. 20, 1928.

T. HARVY PAPER AND PULP MAKING CYLINDER MOLD Filed Aug. 23, 1927 I N V ENTOR.

/1 TTORNEY.

Patented Nov. 20, 1928.l

'ron HARVEY, or urnnmirown, omo.v

PAPER' AND PULP MAKING C'YLIDEB MOLD.

Application med August 2a, um?.` serial No. 21u54.,

v My invention relates to the structure and operation of cylinder molds in paper and pulp making. V

The cylinder mold in a'paper making ma- 5 chine is the large Screensurfaced drumv or roll which revolves in the pulp vat Aand collects the pulp from the paper stock'in this vat, which pulp Yis lifted from .the mold by means of a felt band. The ,felt band passes over the mold and between it and a suct-ion roll or couch roll, the suction of which aids in the lifting ofthe pul forces out a considera 1e quantity of water therefrom, as the felt passes around the roll.

v The usual type of pulp vat is a rectangular tank havin an inlet chamber separated from the mol chamber by a baille. The

paper making stock flows into the inlet chamber and over the baille wall to the mold chamber. Here it must pass through the mold or around it in order. to get to the drainresulting in the collection of the solid matter of the stock on the screen.

To the extent that the stock escapes around land beneath the mold, there is a waste of paper makingmaterials, and also a pollution .of streams into which the paper is drained, that makes trouble for the aper mill both from riparian owners and from the public $0 authorities.

In order to revent this waste it is the' ractice to pack tli the side walls of the vat by means of packing strip engaging around the ends of the mold,

and fastened in this position. This packing does not last, and cannot be maintained tight,- and when it is made tight, the drums are hardto revolve, and cannot be revolved rapidly.

Also, where the felt is used to revolve theA o cylinder molds, the strain on the felt is too great, when the packing is tight.

Another defect of the type of mold of the art lies in the factthat the stock tends to run or slip back downthe cylinder wall as it re-V volves to bring the screened-out pul up to the felt and couch roll, so that the delivery of stock to the felt is not 4as well formed as it should be, and is not always uniform.

Finally, the amount of water in the pulp as it is formed on the screened surface of the4 cylinder mold is too great, or at least much greater than should be required, with the result of loss in heat and power in drying out the stock.

w n is the object of my' iaveneon a) provide from the mold and e space between the mol and" a cylinder mold which is at both ends.

A' hollow shaft forming a continuation of the cyhnder acts as an outlet for the water which vhas passed into the cylinder mold, and is connected with a water circulating pump. This shaft may. be used for setting up' a `small vacuum .within the cylinder. A connection from the hollow shaft is always'made to the water circulating pump andin addition I ma Ause an air' vacuum pum to exhaust the -air wlthinthe cylinder m01 I am thus able to use a regular packed gland for the journals of the cy inder mold in the tank, and all of the water which escapes from the'machine must pass through the screen of the cylinder mold'.

kI can revolve the mold with small power because the glands or stuffing boxes can easily be made` water-.tight without developing great friction, which is' not the case when Ythe mold itself islpacked. The small amount of suction which I am able to. apply to the mold holds the-pulp against slipping back onthe mold and lcauses a thicker and more uniform 'body to be collected upon themold atany given speed of revolution there0f.\ Strains are taken off the felts, and the drainage water is free of pulp, since it will all havebeen thoroughly screened by the mold. I am enabled to make a better paper more rapidly with less waste of materials, and with great economy in power, and can exercise acomplete control of the flow of stock, speed. of the mold, and thickness of the sheet formed on the felt from the mold, and also am able to provide a pulp to t-he felt which ispnot as full of water, as in the usual practice.

I illustrate in the drawings an embodiment of my invention, as anexample of one way of applying the same, and will describe this embodiment in full, and set forth the novelty of my invention in the appended claim.

In the drawings Figure 1 is a side elevation of the machine. i

Figure 2 is an end elevation' taken at the left of Figure 1.

Figure 3 is a perspective of the-one head of the cylinder mold.

Figure 4 is a top plan view vof the machine with the screen surface of the mold broken away.

Figure 5 is a detail sectionof the cylinder Figure 6 is a section on the line of Fi re 5.

he'pulp vat, which 1s of usual shape, has

, the two chambers over which the stock iiows.

'I he felt is indicated at 4, and a couch or suction roll at 5. rlhe arrows in Figure 2 indicate the direction of motion. Paper making y machines may have a series of pulp vats, cylinder molds and couch rolls, dependent upon how many layers are to be built up in making the desired paper web.

The cylinder mold is formed with a surface of screening material, which is of the usual cylinder mold type, and I have not illustrated it in detail, but have indicated the screened surface at 6. Ordinarily it-willbe built up of closely interspaced rods with layers of wire fabric of increasingly small mesh stretched over the rods.

The screened surface is supported by a series of spiders which in the form selected have internal ring shaped portions or hubs 7 and horseshoe shaped spokes 8- on which the Screen is arr nged. These spiders are fixed firmly to a arge central shaft 9, which has a series of holes 10 therein lying in the spaces between the spiders. e

The vone end of the central hollow shaft has a lug fitted therein (Fig. 3), which has a solid) portion 11, spaced arms 12 which lie inside ofthe shaft in the space between the rows of holes lengthwise thereof, and which has a. spindle or shaft portion 13, which extends out through the side wall of the vat. This shaft has a packing gland or stufling Vbox 14 to protect its outlet from the vat, and

I have shown a journal 15 for this spindle, and a drive 16 for the cylinder moldl applied to the said spindle. 4

At the other end 17 of thel hollow shaft,

'it isV extended without holes therein, out

throughv the wall of the vat and its exit is protected'by a gland or stuffing box 18. The

yend. of the shaft portion is supported ina bearing 19, and terminates in an outlet box 20. The entrance of the shaft to the outlet box is protected by a. gland 21, and the shaft is free to revolve in the outlet box. The outlet box has an outlet at 22 for air, and an loutlet at 23 to a pump for removing the water, instead of permitting the water to drain off. by gravity, as in usual construetions.V I have not illustrated an air pump or a waterv pump, but have inscribed on the drawings the points where their conduits will be applied to my device. n

.The cylinder is provided at both ends with solid heads 24 a-nd 25, which completely close the cylinder ends and shaft head 11 closes one end of the hollow central shaft. The other end of the cylinder is closed byconnecting the outlet 23 with the water pump and the outlet 22 with the air pump. In operating the device the water and pulp or stock is pumped yinto the vat whence it flows over the afile into the mold chamber, the mold is driven around and a water pump is preferably applied to the one outlet while an air pump is preferably applied to the other outlet. The Water and pulp cannot escape from the mold vat without passing through the screen and out through the holes lin the central shaft, through the shaft to of it on the mold wall as it rises from the level of the stock. By controlling the outlet .pump the difference of level between the water inside ofthe mold and outside. ofthe mold can be regula-ted, so asvtokeep it as near the lower level of the hollow shaft as is desired.' The 'mold will revolve easily with the felt without any drive of'its own, since there `will be very little yfriction working against it; TheY mold screen does not permit anv appreciable quantity of fibrous stock to pass through it and hence there will be no stream pgllution.

I find in practice that I obtain a better sheet of paper, which is also produced with consid- `erably greater economy -byrthe use of my mechanism, than with the old mold mechanism now employed universally, and that I can control the various elements of thickness,

speed, flow of stock, etc., so as to obtain an accuracyv of control, in contradistinction to the-practice of today, in which the mold operation is` hit or miss, and largely dependent upon the skill of the operator. My felts last longer and the whole operation is more uniform and requires less supervision.

Iclaim as new and desire to secure by Letters Patent, istp In a paper making machine the combina.- tionof a pulp vat, a cylinder mold within the, vat, said mold having closed ends, a hollow' tubular axial support extending through said mold having suction apertures, said support having spiders fixedly mounted thereon su portingr said mold, a lug in one end of said support havingv a rive shaft connected therewith, said support having its other end open, and means for connecting said open end with awater and air escape line.

TOMl HARVEY.

Having thus described my invention, what 

